2001 Chevy Cavalier Ticking noise

Just yesterday I turned on the heater in my car and it started making a ticking noise. I turned up the heater (for more heat) and the noise got faster and a little louder. When I turn it off the noise gets slower and slower until it stops. I don't want to take it to get it checked out yet because they will probably charge me a ridiculous amount for something that may be simple. Any ideas as to what it could be? I'd appreciate any help so much!